I have a growth coming out the side of a psuedobulb, but it looks identical to the new leads that sprout from the base of the plant. I've been reading that this plant spikes half way up the p-bulbs like mine. Though, I've never gotten Den. aggregatum to bloom, so I'm not familiar what the spike looks like.
The spikes are usually pretty spindly looking at first. Maybe they're not getting enough sun? I bought mine from a nursery in hawaii and they were sitting on bark in the hot unfiltered sun there, the p-bulbs were shrivelled but they were flowering like crazy.